A file format is a standard way that information is encoded for storage in a computer file. It specifies how bits are used to encode information in a digital storage medium. File formats may be either proprietary or free and may be either unpublished or open.

File formats often have a published specification describing the encoding method and enabling testing of program intended functionality.[further explanation needed] Not all formats have freely available specification documents, partly because some developers view their specification documents as trade secrets, and partly because other developers never author a formal specification document, letting precedent set by other programs define the format.[clarification needed]

If the developer of a format doesn't publish free specifications, another developer looking to utilize that kind of file must either reverse engineer the file to find out how to read it or acquire the specification document from the format's developers for a fee and by signing a non-disclosure agreement. The latter approach is possible only when a formal specification document exists. Both strategies require significant time, money, or both; therefore, file formats with publicly available specifications tend to be supported by more programs.

Patent law, rather than copyright, is more often used to protect a file format. Although patents for file formats are not directly permitted under US law, some formats encode data using patented algorithms. For example, using compression with the GIF file format requires the use of a patented algorithm, and though the patent owner did not initially enforce their patent, they later began collecting royalty fees. This has resulted in a significant decrease in the use of GIFs, and is partly responsible for the development of the alternative PNG format. However, the patent expired in the US in mid-2003, and worldwide in mid-2004.

Different operating systems have traditionally taken different approaches to determining a particular file's format, with each approach having its own advantages and disadvantages. Most modern operating systems and individual applications need to use all of the following approaches to read "foreign" file formats, if not work with them completely.

One popular method used by many operating systems, including Windows, Mac OS X, CP/M, DOS, VMS, and VM/CMS, is to determine the format of a file based on the end of its name—the letters following the final period. This portion of the filename is known as the filename extension. For example, HTML documents are identified by names that end with .html (or .htm), and GIF images by .gif. In the original FATfilesystem, file names were limited to an eight-character identifier and a three-character extension, known as an 8.3 filename. There are only so many three-letter extensions, so, often any given extension might be linked to more than one program. Many formats still use three-character extensions even though modern operating systems and application programs no longer have this limitation. Since there is no standard list of extensions, more than one format can use the same extension, which can confuse both the operating system and users.

One artifact of this approach is that the system can easily be tricked into treating a file as a different format simply by renaming it—an HTML file can, for instance, be easily treated as plain text by renaming it from filename.html to filename.txt. Although this strategy was useful to expert users who could easily understand and manipulate this information, it was often confusing to less technical users, who could accidentally make a file unusable (or "lose" it) by renaming it incorrectly.

This led more recent operating system shells, such as Windows 95 and Mac OS X, to hide the extension when listing files. This prevents the user from accidentally changing the file type, and allows expert users to turn this feature off and display the extensions.

Hiding the extension, however, can create the appearance of two or more identical filenames in the same folder. For example, a company logo may be needed both in .eps format (for publishing) and .png format (for web sites). With the extensions visible, these would appear as the unique filenames "CompanyLogo.eps" and "CompanyLogo.png". On the other hand, hiding the extensions would make both appear as "CompanyLogo".

Hiding extensions can also pose a security risk.[1] For example, a malicious user could create an executable program with an innocent name such as "Holiday photo.jpg.exe". The ".exe" would be hidden and a user would see "Holiday photo.jpg", which would appear to be a JPEG image, unable to harm the machine save for bugs in the application used to view it. However, the operating system would still see the ".exe" extension and thus run the program, which would then be able to cause harm to the computer. The same is true with files with only one extension: as it is not shown to the user, no information about the file can be deduced without explicitly investigating the file. Extensions can be spoofed. Some Word macro viruses create a Word file in template format and save it with a .DOC extension. Since Word generally ignores extensions and looks at the format of the file these would open as templates, execute, and spread the virus. To further trick users, it is possible to store an icon inside the program, in which case some operating systems' icon assignment for the executable file (.exe) would be overridden with an icon commonly used to represent JPEG images, making the program look like an image. This issue requires users with extensions hidden to be vigilant and never let the operating system choose with what program to open a file not known to be trustworthy (which contradicts the idea of making things easier for the user). This represents a practical problem for Windows systems where extension-hiding is turned on by default.

A second way to identify a file format is to use information regarding the format stored inside the file itself, either information meant for this purpose or binary strings that happen to always be in specific locations in files of some formats. Since the easiest place to locate them is at the beginning, such area is usually called a file header when it is greater than a few bytes, or a magic number if it is just a few bytes long.

The metadata contained in a file header are usually stored at the start of the file, but might be present in other areas too, often including the end, depending on the file format or the type of data contained. Character-based (text) files usually have character-based headers, whereas binary formats usually have binary headers, although this is not a rule. Text-based file headers usually take up more space, but being human-readable, they can easily be examined by using simple software such as a text editor or a hexadecimal editor.

As well as identifying the file format, file headers may contain metadata about the file and its contents. For example, most image files store information about image format, size, resolution and color space, and optionally authoring information such as who made the image, when and where it was made, what camera model and photographic settings were used (Exif), and so on. Such metadata may be used by software reading or interpreting the file during the loading process and afterwards.

File headers may be used by an operating system to quickly gather information about a file without loading it all into memory, but doing so uses more of a computer's resources than reading directly from the directory information. For instance, when a graphicfile manager has to display the contents of a folder, it must read the headers of many files before it can display the appropriate icons, but these will be located in different places on the storage medium thus taking longer to access. A folder containing many files with complex metadata such as thumbnail information may require considerable time before it can be displayed.

If a header is binary hard-coded such that the header itself needs complex interpretation in order to be recognized, especially for metadata content protection's sake, there is a risk that the file format can be misinterpreted. It may even have been badly written at the source. This can result in corrupt metadata which, in extremely bad cases, might even render the file unreadable.[clarification needed]

A more complex example of file headers are those used for wrapper (or container) file formats.

One way to incorporate file type metadata, often associated with Unix and its derivatives, is just to store a "magic number" inside the file itself. Originally, this term was used for a specific set of 2-byte identifiers at the beginnings of files, but since any binary sequence can be regarded as a number, any feature of a file format which uniquely distinguishes it can be used for identification. GIF images, for instance, always begin with the ASCII representation of either GIF87a or GIF89a, depending upon the standard to which they adhere. Many file types, especially plain-text files, are harder to spot by this method. HTML files, for example, might begin with the string <html> (which is not case sensitive), or an appropriate document type definition that starts with <!DOCTYPE HTML>, or, for XHTML, the XML identifier, which begins with <?xml. The files can also begin with HTML comments, random text, or several empty lines, but still be usable HTML.

The magic number approach offers better guarantees that the format will be identified correctly, and can often determine more precise information about the file. Since reasonably reliable "magic number" tests can be fairly complex, and each file must effectively be tested against every possibility in the magic database, this approach is relatively inefficient, especially for displaying large lists of files (in contrast, file name and metadata-based methods need check only one piece of data, and match it against a sorted index). Also, data must be read from the file itself, increasing latency as opposed to metadata stored in the directory. Where file types don't lend themselves to recognition in this way, the system must fall back to metadata. It is, however, the best way for a program to check if the file it has been told to process is of the correct format: while the file's name or metadata may be altered independently of its content, failing a well-designed magic number test is a pretty sure sign that the file is either corrupt or of the wrong type. On the other hand, a valid magic number does not guarantee that the file is not corrupt or is of a correct type.

So-called shebang lines in script files are a special case of magic numbers. Here, the magic number is human-readable text that identifies a specific command interpreter and options to be passed to the command interpreter.

Another operating system using magic numbers is AmigaOS, where magic numbers were called "Magic Cookies" and were adopted as a standard system to recognize executables in Hunk executable file format and also to let single programs, tools and utilities deal automatically with their saved data files, or any other kind of file types when saving and loading data. This system was then enhanced with the Amiga standard Datatype recognition system. Another method was the FourCC method, originating in OSType on Macintosh, later adapted by Interchange File Format (IFF) and derivatives.

A final way of storing the format of a file is to explicitly store information about the format in the file system, rather than within the file itself.

This approach keeps the metadata separate from both the main data and the name, but is also less portable than either file extensions or "magic numbers", since the format has to be converted from filesystem to filesystem. While this is also true to an extent with filename extensions—for instance, for compatibility with MS-DOS's three character limit—most forms of storage have a roughly equivalent definition of a file's data and name, but may have varying or no representation of further metadata.

Note that zip files or archive files solve the problem of handling metadata. A utility program collects multiple files together along with metadata about each file and the folders/directories they came from all within one new file (e.g. a zip file with extension .zip). The new file is also compressed and possibly encrypted, but now is transmissible as a single file across operating systems by FTP systems or attached to email. At the destination, it must be unzipped by a compatible utility to be useful, but the problems of transmission are solved this way.

The Mac OS' Hierarchical File System stores codes for creator and type as part of the directory entry for each file. These codes are referred to as OSTypes. These codes could be any 4-byte sequence, but were often selected so that the ASCII representation formed a sequence of meaningful characters, such as an abbreviation of the application's name or the developer's initials. For instance a HyperCard "stack" file has a creator of WILD (from Hypercard's previous name, "WildCard") and a type of STAK. The BBEdit text editor has a creator code of R*ch referring to its original programmer, Rich Siegel. The type code specifies the format of the file, while the creator code specifies the default program to open it with when double-clicked by the user. For example, the user could have several text files all with the type code of TEXT, but which each open in a different program, due to having differing creator codes. This feature was intended so that, for example, human-readable plain-text files could be opened in a general purpose text editor, while programming or HTML code files would open in a specialized editor or IDE, but this feature was often the source of user confusion as which program would launch when the files were double-clicked was often unpredictable. RISC OS uses a similar system, consisting of a 12-bit number which can be looked up in a table of descriptions—e.g. the hexadecimal number FF5 is "aliased" to PoScript, representing a PostScript file.

A Uniform Type Identifier (UTI) is a method used in Mac OS X for uniquely identifying "typed" classes of entity, such as file formats. It was developed by Apple as a replacement for OSType (type & creator codes).

The UTI is a Core Foundationstring, which uses a reverse-DNS string. Some common and standard types use a domain called public (e.g. public.png for a Portable Network Graphics image), while other domains can be used for third-party types (e.g. com.adobe.pdf for Portable Document Format). UTIs can be defined within a hierarchical structure, known as a conformance hierarchy. Thus, public.png conforms to a supertype of public.image, which itself conforms to a supertype of public.data. A UTI can exist in multiple hierarchies, which provides great flexibility.

In addition to file formats, UTIs can also be used for other entities which can exist in OS X, including:

The HPFS, FAT12 and FAT16 (but not FAT32) filesystems allow the storage of "extended attributes" with files. These comprise an arbitrary set of triplets with a name, a coded type for the value and a value, where the names are unique and values can be up to 64 KB long. There are standardized meanings for certain types and names (under OS/2). One such is that the ".TYPE" extended attribute is used to determine the file type. Its value comprises a list of one or more file types associated with the file, each of which is a string, such as "Plain Text" or "HTML document". Thus a file may have several types.

The NTFS filesystem also allows storage of OS/2 extended attributes, as one of the file forks, but this feature is merely present to support the OS/2 subsystem (not present in XP), so the Win32 subsystem treats this information as an opaque block of data and does not use it. Instead, it relies on other file forks to store meta-information in Win32-specific formats. OS/2 extended attributes can still be read and written by Win32 programs, but the data must be entirely parsed by applications.

On Unix and Unix-like systems, the ext2, ext3, ReiserFS version 3, XFS, JFS, FFS, and HFS+ filesystems allow the storage of extended attributes with files. These include an arbitrary list of "name=value" strings, where the names are unique and a value can be accessed through its related name.

MIME types are widely used in many Internet-related applications, and increasingly elsewhere, although their usage for on-disc type information is rare. These consist of a standardised system of identifiers (managed by IANA) consisting of a type and a sub-type, separated by a slash—for instance, text/html or image/gif. These were originally intended as a way of identifying what type of file was attached to an e-mail, independent of the source and target operating systems. MIME types identify files on BeOS, AmigaOS 4.0 and MorphOS, as well as store unique application signatures for application launching. In AmigaOS and MorphOS the Mime type system works in parallel with Amiga specific Datatype system.

There are problems with the MIME types though; several organisations and people have created their own MIME types without registering them properly with IANA, which makes the use of this standard awkward in some cases.

File format identifiers is another, not widely used way to identify file formats according to their origin and their file category. It was created for the Description Explorer suite of software. It is composed of several digits of the form NNNNNNNNN-XX-YYYYYYY. The first part indicates the organisation origin/maintainer (this number represents a value in a company/standards organisation database), the 2 following digits categorize the type of file in hexadecimal. The final part is composed of the usual file extension of the file or the international standard number of the file, padded left with zeros. For example, the PNG file specification has the FFID of 000000001-31-0015948 where 31 indicates an image file, 0015948 is the standard number and 000000001 indicates the ISO Organisation.

Another but less popular way to identify the file format is to examine the file contents for distinguishable patterns among file types. The contents of a file are a sequence of bytes and a byte has 256 unique permutations (0–255). Thus, counting the occurrence of byte patterns that is often referred as byte frequency distribution gives distinguishable patterns to identify file types. There are many content-based file type identification schemes that use byte frequency distribution to build the representative models for file type and use any statistical and data mining techniques to identify file types [2]

Earlier file formats used raw data formats that consisted of directly dumping the memory images of one or more structures into the file.

This has several drawbacks. Unless the memory images also have reserved spaces for future extensions, extending and improving this type of structured file is very difficult. It also creates files that might be specific to one platform or programming language (for example a structure containing a Pascal string is not recognized as such in C). On the other hand, developing tools for reading and writing these types of files is very simple.

The limitations of the unstructured formats led to the development of other types of file formats that could be easily extended and be backward compatible at the same time.

In this kind of file structure, each piece of data is embedded in a container that somehow identifies the data. The container's scope can be identified by start- and end-markers of some kind, by an explicit length field somewhere, or by fixed requirements of the file format's definition.

Throughout the 1970s, many programs used formats of this general kind. For example, word-processors such as troff, Script, and Scribe, and database export files such as CSV. Electronic Arts and Commodore-Amiga also used this type of file format in 1985, with their IFF (Interchange File Format) file format.

A container is sometimes called a "chunk", although "chunk" may also imply that each piece is small, and/or that chunks do not contain other chunks; many formats do not impose those requirements.

The information that identifies a particular "chunk" may be called many different things, often terms including "field name", "identifier", "label", or "tag". The identifiers are often human-readable, and classify parts of the data: for example, as a "surname", "address", "rectangle", "font name", etc. These are not the same thing as identifiers in the sense of a database key or serial number (although an identifier may well identify its associated data as such a key).

With this type of file structure, tools that do not know certain chunk identifiers simply skip those that they do not understand. Depending on the actual meaning of the skipped data, this may or may not be useful (CSS explicitly defines such behavior).

Indeed, any data format must somehow identify the significance of its component parts, and embedded boundary-markers are an obvious way to do so:

MIME headers do this with a colon-separated label at the start of each logical line. MIME headers cannot contain other MIME headers, though the data content of some headers has sub-parts that can be extracted by other conventions.

CSV and similar files often do this using a header records with field names, and with commas to mark the field boundaries. Like MIME, CSV has no provision for structures with more than one level.

XML and its kin can be loosely considered a kind of chunk-based format, since data elements are identified by markup that is akin to chunk identifiers. However, it has formal advantages such as schemas and validation, as well as the ability to represent more complex structures such as trees, DAGs, and charts. If XML is considered a "chunk" format, then SGML and its predecessor IBM GML are among the earliest examples of such formats.

JSON is similar to XML without schemas, cross-references, or a definition for the meaning of repeated field-names, and is often convenient for programmers.

Protocol buffers are in turn similar to JSON, notably replacing boundary-markers in the data with field numbers, which are mapped to/from names by some external mechanism.

This is another extensible format, that closely resembles a file system (OLE Documents are actual filesystems), where the file is composed of 'directory entries' that contain the location of the data within the file itself as well as its signatures (and in certain cases its type). Good examples of these types of file structures are disk images, OLE documents and TIFF images.

1.
Computer file
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A computer file is a computer resource for recording data discretely in a computer storage device. Just as words can be written to paper, so can information be written to a computer file, there are different types of computer files, designed for different purposes. A file may be designed to store a picture, a message, a video. Some types of files can store different several types of information at once, by using computer programs, a person can open, read, change, and close a computer file. Computer files may be reopened, modified, and copied a number of times. Typically, computer files are organised in a system, which keeps track of where the files are. The word file derives from the Latin filum, such a file now exists in a memory tube developed at RCA Laboratories. Electronically it retains figures fed into calculating machines, holds them in storage while it memorizes new ones - speeds intelligent solutions through mazes of mathematics, in 1952, file denoted, inter alia, information stored on punched cards. In early use, the hardware, rather than the contents stored on it, was denominated a file. For example, the IBM350 disk drives were denominated disk files, although the contemporary register file demonstrates the early concept of files, its use has greatly decreased. On most modern operating systems, files are organized into one-dimensional arrays of bytes, for example, the bytes of a plain text file are associated with either ASCII or UTF-8 characters, while the bytes of image, video, and audio files are interpreted otherwise. Most file types also allocate a few bytes for metadata, which allows a file to some basic information about itself. Some file systems can store arbitrary file-specific data outside of the file format, on other file systems this can be done via sidecar files or software-specific databases. All those methods, however, are susceptible to loss of metadata than are container. At any instant in time, a file might have a size, normally expressed as number of bytes, in most modern operating systems the size can be any non-negative whole number of bytes up to a system limit. Many older operating systems kept track only of the number of blocks or tracks occupied by a file on a storage device. In such systems, software employed other methods to track the exact byte count, the general definition of a file does not require that its size have any real meaning, however, unless the data within the file happens to correspond to data within a pool of persistent storage. A special case is a zero byte file, these files can be newly created files that have not yet had any data written to them, or may serve as some kind of flag in the file system, or are accidents

2.
Portable Network Graphics
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Portable Network Graphics is a raster graphics file format that supports lossless data compression. PNG was created as an improved, non-patented replacement for Graphics Interchange Format, PNG supports palette-based images, grayscale images, and full-color non-palette-based RGB/RGBA images. PNG was designed for transferring images on the Internet, not for professional-quality print graphics, a PNG file contains a single image in an extensible structure of chunks, encoding the basic pixels and other information such as textual comments and integrity checks. PNG files nearly always use file extension PNG or png and are assigned MIME media type image/png, PNG was approved for this use by the Internet Engineering Steering Group on 14 October 1996, and was published as an ISO/IEC standard in 2004. In this thread, Oliver Fromme, author of the popular DOS JPEG viewer QPEG, proposed the PING name, meaning PING is not GIF, although GIF allows for animation, it was decided that PNG should be a single-image format. In 2001, the developers of PNG published the Multiple-image Network Graphics format, MNG achieved moderate application support, but not enough among mainstream web browsers and no usage among web site designers or publishers. In 2008, certain Mozilla developers published the Animated Portable Network Graphics format with similar goals,1 October 1996, Version 1.0 of the PNG specification was released, and later appeared as RFC2083. It became a W3C Recommendation on 1 October 1996,31 December 1998, Version 1.1, with some small changes and the addition of three new chunks, was released. 11 August 1999, Version 1.2, adding one extra chunk, was released,10 November 2003, PNG became an International Standard. This version of PNG differs only slightly from version 1.2, the original PNG specification was authored by an ad-hoc group of computer graphics experts and enthusiasts. Discussions and decisions about the format were done exclusively via email, a chunk consists of four parts, length, chunk type/name, chunk data and CRC. The CRC is a network-byte-order CRC-32 computed over the type and chunk data. Chunk types are given a case sensitive ASCII type/name, compare FourCC. The case of the different letters in the name is a bit field that provides the decoder with some information on the nature of chunks it does not recognize, the case of the first letter indicates whether the chunk is critical or not. If the first letter is uppercase, the chunk is critical, if not, critical chunks contain information that is necessary to read the file. If a decoder encounters a critical chunk it does not recognize, the case of the second letter indicates whether the chunk is public or private. Uppercase is public and lowercase is private and this ensures that public and private chunk names can never conflict with each other. The third letter must be uppercase to conform to the PNG specification and it is reserved for future expansion

3.
Raster graphics
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Raster images are stored in image files with varying formats. A raster is technically characterized by the width and height of the image in pixels, the printing and prepress industries know raster graphics as contones. The opposite to contones is line work, usually implemented as vector graphics in digital systems, the word raster has its origins in the Latin rastrum, which is derived from radere. It originates from the scan of cathode ray tube video monitors. By association, it can refer to a rectangular grid of pixels. The word rastrum is now used to refer to a device for drawing musical staff lines, most modern computers have bitmapped displays, where each on-screen pixel directly corresponds to a small number of bits in memory. The screen is refreshed simply by scanning through pixels and coloring them according to set of bits. The refresh procedure, being speed critical, is implemented by dedicated circuitry. Most computer images are stored in raster graphics formats or compressed variations, including GIF, JPEG, and PNG, three-dimensional voxel raster graphics are employed in video games and are also used in medical imaging such as MRI scanners. GIS programs commonly use rasters that encode geographic data in the values as well as the pixel locations. Raster graphics are resolution dependent, meaning they cannot scale up to a resolution without loss of apparent quality. This property contrasts with the capabilities of graphics, which easily scale up to the quality of the device rendering them. Raster graphics deal more practically than vector graphics with photographs and photo-realistic images, typically, a resolution of 150 to 300 PPI works well for 4-color process printing. However, for printing technologies that perform color mixing through dithering rather than through overprinting, printer DPI and image PPI have a different meaning. Thus, for instance, printing an image at 250 PPI may actually require a printer setting of 1200 DPI, when an image is rendered in a raster-based image editor, the image is composed of millions of pixels. At its core, an image editor works by manipulating each individual pixel. Most pixel-based image editors work using the RGB color model, and this article is based on material taken from the Free On-line Dictionary of Computing prior to 1 November 2008 and incorporated under the relicensing terms of the GFDL, version 1.3 or later

4.
Ogg
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Ogg is a free, open container format maintained by the Xiph. Org Foundation. The creators of the Ogg format state that it is unrestricted by software patents and is designed to provide for efficient streaming and its name is derived from ogging, jargon from the computer game Netrek. The Ogg container format can multiplex a number of independent streams for audio, video, text, in the Ogg multimedia framework, Theora provides a lossy video layer. The audio layer is most commonly provided by the music-oriented Vorbis format or its successor Opus, lossless audio compression formats include FLAC, and OggPCM. Before 2007, the. ogg filename extension was used for all files whose content used the Ogg container format, since 2007, the Xiph. Org Foundation recommends that. ogg only be used for Ogg Vorbis audio files. As of August 4,2011, the current version of the Xiph. Org Foundations reference implementation, is libogg 1.3.0, another version, libogg2, has been in development, but is awaiting a rewrite as of 2008. Both software libraries are free software, released under the New BSD License, Ogg reference implementation was separated from Vorbis on September 2,2000. It is sometimes assumed that the name Ogg comes from the character of Nanny Ogg in Terry Pratchetts Discworld novels, Ogg is derived from ogging, jargon from the computer game Netrek, which came to mean doing something forcefully, possibly without consideration of the drain on future resources. At its inception, the Ogg project was thought to be somewhat ambitious given the power of the PC hardware of the time, still, to quote the same reference, Vorbis, on the other hand is named after the Terry Pratchett character from the book Small Gods. The Ogg Vorbis project started in 1993 and it was originally named Squish but that name was already trademarked, so the project underwent a name change. The new name, OggSquish, was used until 2001 when it was changed again to Ogg, Ogg has since come to refer to the container format, which is now part of the larger Xiph. org multimedia project. Today, Squish refers to an audio coding format typically used with the Ogg container format. The Ogg bitstream format, spearheaded by the Xiph, the format consists of chunks of data each called an Ogg page. Each page begins with the characters, OggS, to identify the file as Ogg format, a serial number and page number in the page header identifies each page as part of a series of pages making up a bitstream. Multiple bitstreams may be multiplexed in the file where pages from each bitstream are ordered by the time of the contained data. Bitstreams may also be appended to existing files, a known as chaining. A BSD-licensed library, called libvorbis, is available to encode and decode data from Vorbis streams, independent Ogg implementations are used in several projects such as RealPlayer and a set of DirectShow filters. Mogg, the Multi-Track-Single-Logical-Stream Ogg-Vorbis, is the multi-channel or multi-track Ogg file format, the following is the field layout of an Ogg page header, Capture pattern –32 bits The capture pattern or sync code is a magic number used to ensure synchronization when parsing Ogg files

5.
Multimedia
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Multimedia is content that uses a combination of different content forms such as text, audio, images, animations, video and interactive content. Multimedia contrasts with media that use only rudimentary computer displays such as text-only or traditional forms of printed or hand-produced material, Multimedia devices are electronic media devices used to store and experience multimedia content. Multimedia is distinguished from mixed media in art, for example. The term rich media is synonymous with interactive multimedia, the term multimedia was coined by singer and artist Bob Goldstein to promote the July 1966 opening of his LightWorks at LOursin show at Southampton, Long Island. Goldstein was perhaps aware of an American artist named Dick Higgins, two years later, in 1968, the term multimedia was re-appropriated to describe the work of a political consultant, David Sawyer, the husband of Iris Sawyer—one of Goldsteins producers at LOursin. In the intervening forty years, the word has taken on different meanings, in the late 1970s, the term referred to presentations consisting of multi-projector slide shows timed to an audio track. However, by the 1990s multimedia took on its current meaning, in the 1993 first edition of Multimedia, Making It Work, Tay Vaughan declared Multimedia is any combination of text, graphic art, sound, animation, and video that is delivered by computer. When you allow the user – the viewer of the project – to control what, when you provide a structure of linked elements through which the user can navigate, interactive multimedia becomes hypermedia. The German language society Gesellschaft für deutsche Sprache recognized the words significance, the institute summed up its rationale by stating has become a central word in the wonderful new media world. In common usage, multimedia refers to an electronically delivered combination of media including video, still images, audio, much of the content on the web today falls within this definition as understood by millions. That era saw also a boost in the production of educational multimedia CD-ROMs, the term video, if not used exclusively to describe motion photography, is ambiguous in multimedia terminology. Video is often used to describe the format, delivery format. Multiple forms of content are often not considered modern forms of presentation such as audio or video. Likewise, single forms of content with single methods of information processing are often called multimedia. Performing arts may also be considered multimedia considering that performers and props are multiple forms of content and media. Multimedia presentations may be viewed by person on stage, projected, transmitted, a broadcast may be a live or recorded multimedia presentation. Broadcasts and recordings can be analog or digital electronic media technology. Digital online multimedia may be downloaded or streamed, streaming multimedia may be live or on-demand

6.
Sound
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In physics, sound is a vibration that propagates as a typically audible mechanical wave of pressure and displacement, through a transmission medium such as air or water. In physiology and psychology, sound is the reception of such waves, humans can hear sound waves with frequencies between about 20 Hz and 20 kHz. Sound above 20 kHz is ultrasound and below 20 Hz is infrasound, other animals have different hearing ranges. Acoustics is the science that deals with the study of mechanical waves in gases, liquids, and solids including vibration, sound, ultrasound. A scientist who works in the field of acoustics is an acoustician, an audio engineer, on the other hand, is concerned with the recording, manipulation, mixing, and reproduction of sound. Auditory sensation evoked by the oscillation described in, sound can propagate through a medium such as air, water and solids as longitudinal waves and also as a transverse wave in solids. The sound waves are generated by a source, such as the vibrating diaphragm of a stereo speaker. The sound source creates vibrations in the surrounding medium, as the source continues to vibrate the medium, the vibrations propagate away from the source at the speed of sound, thus forming the sound wave. At a fixed distance from the source, the pressure, velocity, at an instant in time, the pressure, velocity, and displacement vary in space. Note that the particles of the medium do not travel with the sound wave and this is intuitively obvious for a solid, and the same is true for liquids and gases. During propagation, waves can be reflected, refracted, or attenuated by the medium, the behavior of sound propagation is generally affected by three things, A complex relationship between the density and pressure of the medium. This relationship, affected by temperature, determines the speed of sound within the medium, if the medium is moving, this movement may increase or decrease the absolute speed of the sound wave depending on the direction of the movement. For example, sound moving through wind will have its speed of propagation increased by the speed of the if the sound and wind are moving in the same direction. If the sound and wind are moving in opposite directions, the speed of the wave will be decreased by the speed of the wind. Medium viscosity determines the rate at which sound is attenuated, for many media, such as air or water, attenuation due to viscosity is negligible. When sound is moving through a medium that does not have constant physical properties, the mechanical vibrations that can be interpreted as sound can travel through all forms of matter, gases, liquids, solids, and plasmas. The matter that supports the sound is called the medium, sound cannot travel through a vacuum. Sound is transmitted through gases, plasma, and liquids as longitudinal waves and it requires a medium to propagate

7.
Video
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Video is an electronic medium for the recording, copying, playback, broadcasting, and display of moving visual media. Video systems vary greatly in the resolution of the display and refresh rate, video can be carried on a variety of media, including radio broadcast, tapes, DVDs, computer files etc. Video was originally exclusively a live technology, charles Ginsburg led an Ampex research team developing one of the first practical video tape recorder. In 1951 the first video tape recorder captured live images from television cameras by converting the electrical impulses. Video recorders were sold for $50,000 in 1956, however, prices gradually dropped over the years, in 1971, Sony began selling videocassette recorder decks and tapes into the consumer market. The use of techniques in video created digital video, which allowed higher quality and, eventually. After the invention of the DVD in 1997 and Blu-ray Disc in 2006, sales of videotape, the advent of digital broadcasting and the subsequent digital television transition is in the process of relegating analog video to the status of a legacy technology in most parts of the world. PAL standards and SECAM specify 25 frame/s, while NTSC standards specify 29.97 frames, film is shot at the slower frame rate of 24 frames per second, which slightly complicates the process of transferring a cinematic motion picture to video. The minimum frame rate to achieve a comfortable illusion of an image is about sixteen frames per second. Video can be interlaced or progressive, analog display devices reproduce each frame in the same way, effectively doubling the frame rate as far as perceptible overall flicker is concerned. NTSC, PAL and SECAM are interlaced formats, abbreviated video resolution specifications often include an i to indicate interlacing. For example, PAL video format is specified as 576i50, where 576 indicates the total number of horizontal scan lines, i indicates interlacing. In progressive scan systems, each refresh period updates all scan lines in each frame in sequence, when displaying a natively progressive broadcast or recorded signal, the result is optimum spatial resolution of both the stationary and moving parts of the image. Deinterlacing cannot, however, produce video quality that is equivalent to true progressive scan source material, aspect ratio describes the dimensions of video screens and video picture elements. All popular video formats are rectilinear, and so can be described by a ratio between width and height, the screen aspect ratio of a traditional television screen is 4,3, or about 1.33,1. High definition televisions use a ratio of 16,9. The aspect ratio of a full 35 mm film frame with soundtrack is 1.375,1. Therefore, a 720 by 480 pixel NTSC DV image displayes with the 4,3 aspect ratio if the pixels are thin, the popularity of viewing video on mobile phones has led to the growth of vertical video

8.
Subtitles
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The encoded method can either be pre-rendered with the video or separate as either a graphic or text to be rendered and overlaid by the receiver. Teletext subtitle language follows the audio, except in multi-lingual countries where the broadcaster may provide subtitles in additional languages on other teletext pages. EIA-608 captions are similar, except that North American Spanish stations may provide captioning in Spanish on CC3, DVD and Blu-ray only differ in using run-length encoded graphics instead of text, as well as some HD DVB broadcasts. Sometimes, mainly at festivals, subtitles may be shown on a separate display below the screen. Television subtitling for the deaf and hard of hearing is referred to as closed captioning in some countries. The word subtitle is the prefix followed by title. In some cases, such as opera, the dialog is displayed above the stage in what are referred to as surtitles. Today, professional subtitlers usually work with specialized software and hardware where the video is digitally stored on a hard disk. Besides creating the subtitles, the subtitler usually also tells the computer software the exact positions where each subtitle should appear and disappear, for cinema film, this task is traditionally done by separate technicians. The end result is a file containing the actual subtitles as well as position markers indicating where each subtitle should appear and disappear. These markers are based on timecode if it is a work for electronic media. For multimedia-style Webcasting, check, SMIL Synchronized Multimedia Integration Language, same-language captions, i. e. without translation, were primarily intended as an aid for people who are deaf or hard of hearing. Internationally, there are several studies which demonstrate that same-language captioning can have a major impact on literacy. This method of subtitling is used by television broadcasters in China. Same Language Subtitling is the use of Synchronized Captioning of Musical Lyrics as a Repeated Reading activity, the basic reading activity involves students viewing a short subtitled presentation projected onscreen, while completing a response worksheet. Closed captioning is the American term for closed subtitles specifically intended for people who are deaf and these are a transcription rather than a translation, and usually contain descriptions of important non-dialog audio as well such as or and lyrics. From the expression closed captions the word caption has in recent years come to mean a subtitle intended for the hard of hearing, be it open or closed. In British English subtitles usually refers to subtitles for the hard of hearing, however, programs such as news bulletins, current affairs programs, sport, some talk shows and political and special events utilize real time or online captioning

9.
Text file
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A text file is a kind of computer file that is structured as a sequence of lines of electronic text. A text file exists within a file system. The end of a file is often denoted by placing one or more special characters. Such markers were required under the CP/M and MS-DOS operating systems, on modern operating systems such as Windows and Unix-like systems, text files do not contain any special EOF character. Text file refers to a type of container, while plain text refers to a type of content, Text files can contain plain text, but they are not limited to such. At a generic level of description, there are two kinds of files, text files and binary files. Because of their simplicity, text files are used for storage of information. They avoid some of the problems encountered with other formats, such as endianness, padding bytes. Further, when data corruption occurs in a file, it is often easier to recover. A disadvantage of text files is that usually have a low entropy. A simple text file needs no additional metadata to assist the reader in interpretation, and therefore may contain no data at all, the ASCII character set is the most common format for English-language text files, and is generally assumed to be the default file format in many situations. For accented and other characters, it is necessary to choose a character encoding. In many systems, this is chosen on the basis of the locale setting on the computer it is read on. Common character encodings include ISO 8859-1 for many European languages, because many encodings have only a limited repertoire of characters, they are often only usable to represent text in a limited subset of human languages. Unicode is an attempt to create a standard for representing all known languages. On most operating systems the name text file refers to file format that only plain text content with very little formatting. Such files can be viewed and edited on text terminals or in text editors. Text files usually have the MIME type text/plain, usually with additional information indicating an encoding, MS-DOS and Windows use a common text file format, with each line of text separated by a two-character combination, carriage return and line feed

10.
HTML
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Hypertext Markup Language is the standard markup language for creating web pages and web applications. With Cascading Style Sheets and JavaScript it forms a triad of cornerstone technologies for the World Wide Web, Web browsers receive HTML documents from a webserver or from local storage and render them into multimedia web pages. HTML describes the structure of a web page semantically and originally included cues for the appearance of the document, HTML elements are the building blocks of HTML pages. With HTML constructs, images and other objects, such as interactive forms and it provides a means to create structured documents by denoting structural semantics for text such as headings, paragraphs, lists, links, quotes and other items. HTML elements are delineated by tags, written using angle brackets, tags such as <img /> and <input /> introduce content into the page directly. Include explicit close tags for elements that permit content but are left empty, by carefully following the W3Cs compatibility guidelines, a user agent should be able to interpret the document equally as HTML or XHTML. For documents that are XHTML1.0 and have made compatible in this way. When delivered as XHTML, browsers should use an XML parser, HTML4 defined three different versions of the language, Strict, Transitional and Frameset. The Transitional and Frameset versions allow for presentational markup, which is omitted in the Strict version, instead, cascading style sheets are encouraged to improve the presentation of HTML documents. Because XHTML1 only defines an XML syntax for the language defined by HTML4, as this list demonstrates, the loose versions of the specification are maintained for legacy support. However, contrary to popular misconceptions, the move to XHTML does not imply a removal of this legacy support, rather the X in XML stands for extensible and the W3C is modularizing the entire specification and opening it up to independent extensions. The primary achievement in the move from XHTML1.0 to XHTML1.1 is the modularization of the entire specification, the strict version of HTML is deployed in XHTML1.1 through a set of modular extensions to the base XHTML1.1 specification. Likewise, someone looking for the loose or frameset specifications will find similar extended XHTML1.1 support, the modularization also allows for separate features to develop on their own timetable. So for example, XHTML1.1 will allow quicker migration to emerging XML standards such as MathML, in summary, the HTML4 specification primarily reined in all the various HTML implementations into a single clearly written specification based on SGML. XHTML1.0, ported this specification, as is, next, XHTML1.1 takes advantage of the extensible nature of XML and modularizes the whole specification. XHTML2.0 was intended to be the first step in adding new features to the specification in a standards-body-based approach. The WHATWG considers their work as living standard HTML for what constitutes the state of the art in major browser implementations by Apple, Google, Mozilla, Opera, hTML5 is specified by the HTML Working Group of the W3C following the W3C process. HTML lacks some of the found in earlier hypertext systems, such as source tracking, fat links

11.
Scalable vector graphics
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Scalable Vector Graphics is an XML-based vector image format for two-dimensional graphics with support for interactivity and animation. The SVG specification is a standard developed by the World Wide Web Consortium since 1999. SVG images and their behaviors are defined in XML text files and this means that they can be searched, indexed, scripted, and compressed. As XML files, SVG images can be created and edited with any text editor, All major modern web browsers—including Mozilla Firefox, Internet Explorer, Google Chrome, Opera, Safari, and Microsoft Edge—have SVG rendering support. SVG has been in development within the World Wide Web Consortium since 1999, the early SVG Working Group decided not to develop any of the commercial submissions, but to create a new markup language that was informed by but not really based on any of them. SVG allows three types of objects, vector graphic shapes such as paths and outlines consisting of straight lines and curves, bitmap images. Graphical objects can be grouped, styled, transformed and composited into previously rendered objects, the feature set includes nested transformations, clipping paths, alpha masks, filter effects and template objects. SVG drawings can be interactive and can include animation, defined in the SVG XML elements or via scripting that accesses the SVG Document Object Model, SVG uses CSS for styling and JavaScript for scripting. Text, including internationalization and localization, appearing in plain text within the SVG DOM enhances the accessibility of SVG graphics, the SVG specification was updated to version 1.1 in 2011. There are two Mobile SVG Profiles, SVG Tiny and SVG Basic, meant for mobile devices with reduced computational, Scalable Vector Graphics 2 became a W3C Candidate Recommendation on 15 September 2016. SVG2 incorporates several new features in addition to those of SVG1.1, though the SVG Specification primarily focuses on vector graphics markup language, its design includes the basic capabilities of a page description language like Adobes PDF. It contains provisions for rich graphics, and is compatible with CSS for styling purposes, SVG has the information needed to place each glyph and image in a chosen location on a printed page. A print-specialized subset of SVG is currently a W3C Working Draft, SVG drawings can be dynamic and interactive. Time-based modifications to the elements can be described in SMIL, or can be programmed in a scripting language, the W3C explicitly recommends SMIL as the standard for animation in SVG. A rich set of event handlers such as onmouseover and onclick can be assigned to any SVG graphical object, SVG images, being XML, contain many repeated fragments of text, so they are well suited for lossless data compression algorithms. When an SVG image has been compressed with the industry standard gzip algorithm, it is referred to as an SVGZ image, conforming SVG1.1 viewers will display compressed images. An SVGZ file is typically 20 to 50 percent of the original size, W3C provides SVGZ files to test for conformance. SVG1.0 became a W3C Recommendation on 4 September 2001, SVG1.1 became a W3C Recommendation on 14 January 2003

12.
Source code
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In computing, source code is any collection of computer instructions, possibly with comments, written using a human-readable programming language, usually as ordinary text. The source code of a program is designed to facilitate the work of computer programmers. The source code is often transformed by an assembler or compiler into binary machine code understood by the computer, the machine code might then be stored for execution at a later time. Alternatively, source code may be interpreted and thus immediately executed, most application software is distributed in a form that includes only executable files. If the source code were included it would be useful to a user, programmer or a system administrator, the Linux Information Project defines source code as, Source code is the version of software as it is originally written by a human in plain text. The notion of source code may also be more broadly, to include machine code and notations in graphical languages. It is therefore so construed as to include code, very high level languages. Often there are several steps of program translation or minification between the source code typed by a human and an executable program. The earliest programs for stored-program computers were entered in binary through the front panel switches of the computer and this first-generation programming language had no distinction between source code and machine code. When IBM first offered software to work with its machine, the code was provided at no additional charge. At that time, the cost of developing and supporting software was included in the price of the hardware, for decades, IBM distributed source code with its software product licenses, until 1983. Most early computer magazines published source code as type-in programs, Source code can also be stored in a database or elsewhere. The source code for a piece of software may be contained in a single file or many files. Though the practice is uncommon, a source code can be written in different programming languages. For example, a program written primarily in the C programming language, in some languages, such as Java, this can be done at run time. The code base of a programming project is the larger collection of all the source code of all the computer programs which make up the project. It has become practice to maintain code bases in version control systems. Moderately complex software customarily requires the compilation or assembly of several, sometimes dozens or even hundreds, in these cases, instructions for compilations, such as a Makefile, are included with the source code

13.
Syntax
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In linguistics, syntax is the set of rules, principles, and processes that govern the structure of sentences in a given language, specifically word order. The term syntax is used to refer to the study of such principles and processes. The goal of many syntacticians is to discover the syntactic rules common to all languages, in mathematics, syntax refers to the rules governing the behavior of mathematical systems, such as formal languages used in logic. The word syntax comes from Ancient Greek, σύνταξις coordination, which consists of σύν syn, together, and τάξις táxis, a basic feature of a languages syntax is the sequence in which the subject, verb, and object usually appear in sentences. Over 85% of languages usually place the subject first, either in the sequence SVO or the sequence SOV, the other possible sequences are VSO, VOS, OVS, and OSV, the last three of which are rare. In the West, the school of thought came to be known as traditional grammar began with the work of Dionysius Thrax. For centuries, work in syntax was dominated by a known as grammaire générale. This system took as its premise the assumption that language is a direct reflection of thought processes and therefore there is a single. It became apparent that there was no such thing as the most natural way to express a thought, the Port-Royal grammar modeled the study of syntax upon that of logic. Syntactic categories were identified with logical ones, and all sentences were analyzed in terms of Subject – Copula – Predicate, initially, this view was adopted even by the early comparative linguists such as Franz Bopp. The central role of syntax within theoretical linguistics became clear only in the 20th century, there are a number of theoretical approaches to the discipline of syntax. One school of thought, founded in the works of Derek Bickerton, sees syntax as a branch of biology, other linguists take a more Platonistic view, since they regard syntax to be the study of an abstract formal system. Yet others consider syntax a taxonomical device to reach broad generalizations across languages, the hypothesis of generative grammar is that language is a structure of the human mind. The goal of grammar is to make a complete model of this inner language. This model could be used to all human language and to predict the grammaticality of any given utterance. This approach to language was pioneered by Noam Chomsky, most generative theories assume that syntax is based upon the constituent structure of sentences. Generative grammars are among the theories that focus primarily on the form of a sentence and this complex category is notated as instead of V. NP\S is read as a category that searches to the left for an NP and outputs a sentence. The category of verb is defined as an element that requires two NPs to form a sentence

14.
Trade secret
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The precise language by which a trade secret is defined varies by jurisdiction. These three aspects are incorporated in the TRIPS Agreement in Article 39. By comparison, under U. S. law, A trade secret, §1839, has three parts, information, reasonable measures taken to protect the information, and which derives independent economic value from not being publicly known. Trade secrets are an important, but invisible component of an intellectual property. Their contribution to a value, measured as its market capitalization. Being invisible, that contribution is hard to measure, patents are a visible contribution, but delayed, and unsuitable for internal innovations. Having an internal scoreboard provides insight into the cost of risks of leaving to serve or start competing ventures. In contrast to registered intellectual property, trade secrets are, by definition, instead, owners of trade secrets seek to protect trade secret information from competitors by instituting special procedures for handling it, as well as technological and legal security measures. Legal protections include non-disclosure agreements, and work-for-hire and non-compete clauses, violation of the agreement generally carries the possibility of heavy financial penalties which operate as a disincentive to reveal trade secrets. However, proving a breach of an NDA by a stakeholder who is legally working for a competitor or prevailing in a lawsuit for breaching a non-compete clause can be very difficult. A holder of a secret may also require similar agreements from other parties he or she deals with, such as vendors, licensees. Therefore, trade secrets such as secret formulae are often protected by restricting the key information to a few trusted individuals, famous examples of products protected by trade secrets are Chartreuse liqueur and Coca-Cola. In fact, Coca-Cola refused to reveal its trade secret under at least two judges orders, acts of industrial espionage are generally illegal in their own right under the relevant governing laws, and penalties can be harsh. The importance of that illegality to trade secret law is, if a secret is acquired by improper means. Thus, if a secret has been acquired via industrial espionage. Commentators starting with A. Arthur Schiller assert that trades secrets were protected under Roman law by a known as actio servi corrupti. The Roman law is described as follows, he Roman owner of a mark or firm name was protected against unfair usage by a competitor through the actio servi corrupti. Which the Roman jurists used to grant commercial relief under the guise of private law actions

15.
Patent
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A patent is a set of exclusive rights granted by a sovereign state to an inventor or assignee for a limited period of time in exchange for detailed public disclosure of an invention. An invention is a solution to a technological problem and is a product or a process. Patents are a form of intellectual property, the procedure for granting patents, requirements placed on the patentee, and the extent of the exclusive rights vary widely between countries according to national laws and international agreements. Typically, however, a patent application must include one or more claims that define the invention. A patent may include many claims, each of which defines a specific property right and these claims must meet relevant patentability requirements, such as novelty, usefulness, and non-obviousness. Nevertheless, there are variations on what is patentable subject matter from country to country, the word patent originates from the Latin patere, which means to lay open. More directly, it is a version of the term letters patent. Similar grants included land patents, which were land grants by early state governments in the USA, and printing patents, a precursor of modern copyright. In modern usage, the term patent usually refers to the granted to anyone who invents any new, useful. The additional qualification utility patent is used to distinguish the primary meaning from these other types of patents. Particular species of patents for inventions include biological patents, business method patents, chemical patents, the period of protection was 10 years. These were mostly in the field of glass making, as Venetians emigrated, they sought similar patent protection in their new homes. This led to the diffusion of patent systems to other countries, by the 16th century, the English Crown would habitually abuse the granting of letters patent for monopolies. After public outcry, King James I of England was forced to revoke all existing monopolies, the Statute became the foundation for later developments in patent law in England and elsewhere. Important developments in patent law emerged during the 18th century through a process of judicial interpretation of the law. During the reign of Queen Anne, patent applications were required to supply a complete specification of the principles of operation of the invention for public access. Influenced by the philosophy of John Locke, the granting of patents began to be viewed as a form of property right. The English legal system became the foundation for patent law in countries with a common law heritage, including the United States, New Zealand, in the Thirteen Colonies, inventors could obtain patents through petition to a given colonys legislature

16.
Copyright
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Copyright is a legal right created by the law of a country that grants the creator of an original work exclusive rights for its use and distribution. This is usually only for a limited time, the exclusive rights are not absolute but limited by limitations and exceptions to copyright law, including fair use. A major limitation on copyright is that copyright protects only the expression of ideas. Copyright is a form of property, applicable to certain forms of creative work. Some, but not all jurisdictions require fixing copyrighted works in a tangible form and it is often shared among multiple authors, each of whom holds a set of rights to use or license the work, and who are commonly referred to as rights holders. These rights frequently include reproduction, control over derivative works, distribution, public performance, copyrights are considered territorial rights, which means that they do not extend beyond the territory of a specific jurisdiction. While many aspects of copyright laws have been standardized through international copyright agreements. Typically, the duration of a copyright spans the authors life plus 50 to 100 years, some countries require certain copyright formalities to establishing copyright, but most recognize copyright in any completed work, without formal registration. Generally, copyright is enforced as a matter, though some jurisdictions do apply criminal sanctions. Most jurisdictions recognize copyright limitations, allowing fair exceptions to the exclusivity of copyright. Copyright came about with the invention of the press and with wider literacy. As a legal concept, its origins in Britain were from a reaction to printers monopolies at the beginning of the 18th century, Copyright laws allow products of creative human activities, such as literary and artistic production, to be preferentially exploited and thus incentivized. Different cultural attitudes, social organizations, economic models and legal frameworks are seen to account for why copyright emerged in Europe and not, for example, however, with copyright laws, intellectual production comes to be seen as a product of an individual, with attendant rights. The most significant point is that patent and copyright laws support the expansion of the range of human activities that can be commodified. This parallels the ways in which led to the commodification of many aspects of social life that earlier had no monetary or economic value per se. Often seen as the first real copyright law, the 1709 British Statute of Anne gave the rights for a fixed period. The act also alluded to individual rights of the artist and it began, Whereas Printers, Booksellers, and other Persons, have of late frequently taken the Liberty of Printing. Books, and other Writings, without the Consent of the Authors. to their very great Detriment, and too often to the Ruin of them and their Families

17.
Algorithms
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In mathematics and computer science, an algorithm is a self-contained sequence of actions to be performed. Algorithms can perform calculation, data processing and automated reasoning tasks, an algorithm is an effective method that can be expressed within a finite amount of space and time and in a well-defined formal language for calculating a function. The transition from one state to the next is not necessarily deterministic, some algorithms, known as randomized algorithms, giving a formal definition of algorithms, corresponding to the intuitive notion, remains a challenging problem. In English, it was first used in about 1230 and then by Chaucer in 1391, English adopted the French term, but it wasnt until the late 19th century that algorithm took on the meaning that it has in modern English. Another early use of the word is from 1240, in a manual titled Carmen de Algorismo composed by Alexandre de Villedieu and it begins thus, Haec algorismus ars praesens dicitur, in qua / Talibus Indorum fruimur bis quinque figuris. Which translates as, Algorism is the art by which at present we use those Indian figures, the poem is a few hundred lines long and summarizes the art of calculating with the new style of Indian dice, or Talibus Indorum, or Hindu numerals. An informal definition could be a set of rules that precisely defines a sequence of operations, which would include all computer programs, including programs that do not perform numeric calculations. Generally, a program is only an algorithm if it stops eventually, but humans can do something equally useful, in the case of certain enumerably infinite sets, They can give explicit instructions for determining the nth member of the set, for arbitrary finite n. An enumerably infinite set is one whose elements can be put into one-to-one correspondence with the integers, the concept of algorithm is also used to define the notion of decidability. That notion is central for explaining how formal systems come into being starting from a set of axioms. In logic, the time that an algorithm requires to complete cannot be measured, from such uncertainties, that characterize ongoing work, stems the unavailability of a definition of algorithm that suits both concrete and abstract usage of the term. Algorithms are essential to the way computers process data, thus, an algorithm can be considered to be any sequence of operations that can be simulated by a Turing-complete system. Although this may seem extreme, the arguments, in its favor are hard to refute. Gurevich. Turings informal argument in favor of his thesis justifies a stronger thesis, according to Savage, an algorithm is a computational process defined by a Turing machine. Typically, when an algorithm is associated with processing information, data can be read from a source, written to an output device. Stored data are regarded as part of the state of the entity performing the algorithm. In practice, the state is stored in one or more data structures, for some such computational process, the algorithm must be rigorously defined, specified in the way it applies in all possible circumstances that could arise. That is, any conditional steps must be dealt with, case-by-case

18.
GIF
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The format supports up to 8 bits per pixel for each image, allowing a single image to reference its own palette of up to 256 different colors chosen from the 24-bit RGB color space. It also supports animations and allows a separate palette of up to 256 colors for each frame, GIF images are compressed using the Lempel–Ziv–Welch lossless data compression technique to reduce the file size without degrading the visual quality. This compression technique was patented in 1985, controversy over the licensing agreement between the software patent holder, Unisys, and CompuServe in 1994 spurred the development of the Portable Network Graphics standard. By 2004 all the relevant patents had expired, CompuServe introduced the GIF format in 1987 to provide a color image format for their file downloading areas, replacing their earlier run-length encoding format, which was black and white only. The original version of the GIF format was called 87a, in 1989, CompuServe released an enhanced version, called 89a, which added support for animation delays, transparent background colors, and storage of application-specific metadata. The 89a specification also supports incorporating text labels as text, but as there is control over display fonts. The two versions can be distinguished by looking at the first six bytes of the file, which, CompuServe encouraged the adoption of GIF by providing downloadable conversion utilities for many computers. By December 1987, for example, an Apple IIGS user could view pictures created on an Atari ST or Commodore 64, GIF was one of the first two image formats commonly used on Web sites, the other being the black-and-white XBM. In September 1995 Netscape Navigator 2.0 added Animated GIF support, the feature of storing multiple images in one file, accompanied by control data, is used extensively on the Web to produce simple animations. As a noun, the word GIF is found in the editions of many dictionaries. In 2012, the American wing of the Oxford University Press recognized GIF as a verb as well, meaning to create a GIF file, as in GIFing was perfect medium for sharing scenes from the Summer Olympics. The presss lexicographers voted it their word of the year, saying that GIFs have evolved into a tool with serious applications including research, in May 2015 Facebook added GIF support, even though they originally didnt support them on their site. The creators of the format pronounced the word as jif with a soft G /ˈdʒɪf/ as in gin, the word is now also widely pronounced with a hard G /ˈɡɪf/ as in gift. The American Heritage Dictionary cites both, indicating jif as the pronunciation, while Cambridge Dictionary of American English offers only the hard-G pronunciation. Merriam-Websters Collegiate Dictionary and the OED cite both pronunciations, but place gif in the default position, the New Oxford American Dictionary gave only jif in its 2nd edition but updated it to jif, gif in its 3rd edition. The disagreement over the pronunciation led to heated Internet debate, the White House and TV program Jeopardy. Also waded into the debate during 2013, GIFs are suitable for sharp-edged line art with a limited number of colors. This takes advantage of the formats lossless compression, which favors flat areas of color with well defined edges

19.
Royalty payment
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A royalty is a payment made by one party, the licensee or franchisee to another that owns a particular asset, the licensor or franchisor for the right to ongoing use of that asset. A royalty interest is the right to collect a stream of future royalty payments, license agreements can be regulated, particularly where a government is the resource owner, or they can be private contracts that follow a general structure. However, certain types of agreements have comparable provisions. When a government owns the resource in question, the transaction is subject to legal. In the United States, fee simple ownership of the mineral is possible by a private individual, local taxing authorities may impose a severance tax on the unrenewable natural resources extracted from within their authority. The Federal Government receives royalties on production on federal lands, managed by the Bureau of Ocean Energy Management, Regulation and Enforcement, an example from Canadas north is the federal Frontier Lands petroleum royalty regime. In this manner risks and profits are shared between the government of Canada and the petroleum developer and this attractive royalty rate is intended to encourage oil and gas exploration in the remote Canadian frontier lands where costs and risks are higher than other locations. In many jurisdictions oil and gas royalty interests are considered property under the NAICS classification code. As a standard example, for every $100 bbl of oil sold on a U. S. federal well with a 25% royalty, the U. S. government does not pay and will only collect revenues. All risk and liability lie upon the operator of the well, Royalties in the forestry industry are called stumpage. An intangible asset such as a patent gives the owner an exclusive right to prevent others from practicing the patented technology in the country issuing the patent for the term of the patent. The right may be enforced in a lawsuit for monetary damages and/or imprisonment for violation on the patent, patent rights may be divided and licensed out in various ways, on an exclusive or non-exclusive basis. The license may be subject to limitations as to time or territory, a license may encompass an entire technology or it may involve a mere component or improvement on a technology. In the United States, reasonable royalties may be imposed, both after-the-fact and prospectively, by a court as a remedy for infringement. 0%, however, the range extended from 0% to 50%. All of these agreements may not have been at arms length, in license negotiation, firms might derive royalties for the use of a patented technology from the retail price of the downstream licensed product. In the Arab countries, it may be found, that a royalty as a percentage of sales may be difficult to transact, a flat fee may be preferred as percentages may be interpreted as percentage of profit. Trade marks are words, logos, slogans, sounds, or other expressions that distinguish the source, origin. Trade marks offer the public a means of identifying and assuring themselves of the quality of the good or service and they may bring consumers a sense of security, integrity, belonging, and a variety of intangible appeals

20.
Operating system
–
An operating system is system software that manages computer hardware and software resources and provides common services for computer programs. All computer programs, excluding firmware, require a system to function. Operating systems are found on many devices that contain a computer – from cellular phones, the dominant desktop operating system is Microsoft Windows with a market share of around 83. 3%. MacOS by Apple Inc. is in place, and the varieties of Linux is in third position. Linux distributions are dominant in the server and supercomputing sectors, other specialized classes of operating systems, such as embedded and real-time systems, exist for many applications. A single-tasking system can run one program at a time. Multi-tasking may be characterized in preemptive and co-operative types, in preemptive multitasking, the operating system slices the CPU time and dedicates a slot to each of the programs. Unix-like operating systems, e. g. Solaris, Linux, cooperative multitasking is achieved by relying on each process to provide time to the other processes in a defined manner. 16-bit versions of Microsoft Windows used cooperative multi-tasking, 32-bit versions of both Windows NT and Win9x, used preemptive multi-tasking. Single-user operating systems have no facilities to distinguish users, but may allow multiple programs to run in tandem, a distributed operating system manages a group of distinct computers and makes them appear to be a single computer. The development of networked computers that could be linked and communicate with each other gave rise to distributed computing, distributed computations are carried out on more than one machine. When computers in a work in cooperation, they form a distributed system. The technique is used both in virtualization and cloud computing management, and is common in large server warehouses, embedded operating systems are designed to be used in embedded computer systems. They are designed to operate on small machines like PDAs with less autonomy and they are able to operate with a limited number of resources. They are very compact and extremely efficient by design, Windows CE and Minix 3 are some examples of embedded operating systems. A real-time operating system is a system that guarantees to process events or data by a specific moment in time. A real-time operating system may be single- or multi-tasking, but when multitasking, early computers were built to perform a series of single tasks, like a calculator. Basic operating system features were developed in the 1950s, such as resident monitor functions that could run different programs in succession to speed up processing

21.
Microsoft Windows
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Microsoft Windows is a metafamily of graphical operating systems developed, marketed, and sold by Microsoft. It consists of families of operating systems, each of which cater to a certain sector of the computing industry with the OS typically associated with IBM PC compatible architecture. Active Windows families include Windows NT, Windows Embedded and Windows Phone, defunct Windows families include Windows 9x, Windows 10 Mobile is an active product, unrelated to the defunct family Windows Mobile. Microsoft introduced an operating environment named Windows on November 20,1985, Microsoft Windows came to dominate the worlds personal computer market with over 90% market share, overtaking Mac OS, which had been introduced in 1984. Apple came to see Windows as an encroachment on their innovation in GUI development as implemented on products such as the Lisa. On PCs, Windows is still the most popular operating system, however, in 2014, Microsoft admitted losing the majority of the overall operating system market to Android, because of the massive growth in sales of Android smartphones. In 2014, the number of Windows devices sold was less than 25% that of Android devices sold and this comparison however may not be fully relevant, as the two operating systems traditionally target different platforms. As of September 2016, the most recent version of Windows for PCs, tablets, smartphones, the most recent versions for server computers is Windows Server 2016. A specialized version of Windows runs on the Xbox One game console, Microsoft, the developer of Windows, has registered several trademarks each of which denote a family of Windows operating systems that target a specific sector of the computing industry. It now consists of three operating system subfamilies that are released almost at the time and share the same kernel. Windows, The operating system for personal computers, tablets. The latest version is Windows 10, the main competitor of this family is macOS by Apple Inc. for personal computers and Android for mobile devices. Windows Server, The operating system for server computers, the latest version is Windows Server 2016. Unlike its clients sibling, it has adopted a strong naming scheme, the main competitor of this family is Linux. Windows PE, A lightweight version of its Windows sibling meant to operate as an operating system, used for installing Windows on bare-metal computers. The latest version is Windows PE10.0.10586.0, Windows Embedded, Initially, Microsoft developed Windows CE as a general-purpose operating system for every device that was too resource-limited to be called a full-fledged computer. The following Windows families are no longer being developed, Windows 9x, Microsoft now caters to the consumers market with Windows NT. Windows Mobile, The predecessor to Windows Phone, it was a mobile operating system

22.
Mac OS X
–
Within the market of desktop, laptop and home computers, and by web usage, it is the second most widely used desktop OS after Microsoft Windows. Launched in 2001 as Mac OS X, the series is the latest in the family of Macintosh operating systems, Mac OS X succeeded classic Mac OS, which was introduced in 1984, and the final release of which was Mac OS9 in 1999. An initial, early version of the system, Mac OS X Server 1.0, was released in 1999, the first desktop version, Mac OS X10.0, followed in March 2001. In 2012, Apple rebranded Mac OS X to OS X. Releases were code named after big cats from the release up until OS X10.8 Mountain Lion. Beginning in 2013 with OS X10.9 Mavericks, releases have been named after landmarks in California, in 2016, Apple rebranded OS X to macOS, adopting the nomenclature that it uses for their other operating systems, iOS, watchOS, and tvOS. The latest version of macOS is macOS10.12 Sierra, macOS is based on technologies developed at NeXT between 1985 and 1997, when Apple acquired the company. The X in Mac OS X and OS X is pronounced ten, macOS shares its Unix-based core, named Darwin, and many of its frameworks with iOS, tvOS and watchOS. A heavily modified version of Mac OS X10.4 Tiger was used for the first-generation Apple TV, Apple also used to have a separate line of releases of Mac OS X designed for servers. Beginning with Mac OS X10.7 Lion, the functions were made available as a separate package on the Mac App Store. Releases of Mac OS X from 1999 to 2005 can run only on the PowerPC-based Macs from the time period, Mac OS X10.5 Leopard was released as a Universal binary, meaning the installer disc supported both Intel and PowerPC processors. In 2009, Apple released Mac OS X10.6 Snow Leopard, in 2011, Apple released Mac OS X10.7 Lion, which no longer supported 32-bit Intel processors and also did not include Rosetta. All versions of the system released since then run exclusively on 64-bit Intel CPUs, the heritage of what would become macOS had originated at NeXT, a company founded by Steve Jobs following his departure from Apple in 1985. There, the Unix-like NeXTSTEP operating system was developed, and then launched in 1989 and its graphical user interface was built on top of an object-oriented GUI toolkit using the Objective-C programming language. This led Apple to purchase NeXT in 1996, allowing NeXTSTEP, then called OPENSTEP, previous Macintosh operating systems were named using Arabic numerals, e. g. Mac OS8 and Mac OS9. The letter X in Mac OS Xs name refers to the number 10 and it is therefore correctly pronounced ten /ˈtɛn/ in this context. However, a common mispronunciation is X /ˈɛks/, consumer releases of Mac OS X included more backward compatibility. Mac OS applications could be rewritten to run natively via the Carbon API, the consumer version of Mac OS X was launched in 2001 with Mac OS X10.0. Reviews were variable, with praise for its sophisticated, glossy Aqua interface

23.
CP/M
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Initially confined to single-tasking on 8-bit processors and no more than 64 kilobytes of memory, later versions of CP/M added multi-user variations and were migrated to 16-bit processors. The combination of CP/M and S-100 bus computers was loosely patterned on the MITS Altair and this computer platform was widely used in business through the late 1970s and into the mid-1980s. CP/M increased the size for both hardware and software by greatly reducing the amount of programming required to install an application on a new manufacturers computer. An important driver of innovation was the advent of low-cost microcomputers running CP/M, as independent programmers and hackers bought them. CP/M was displaced by MS-DOS soon after the 1981 introduction of the IBM PC, manufacturers of CP/M-compatible systems customized portions of the operating system for their own combination of installed memory, disk drives, and console devices. CP/M would also run on based on the Zilog Z80 processor since the Z80 was compatible with 8080 code. CP/M used the 7-bit ASCII set, the other 128 characters made possible by the 8-bit byte were not standardized. For example, one Kaypro used them for Greek characters, WordStar used the 8th bit as an end-of-word marker. The BIOS and BDOS were memory-resident, while the CCP was memory-resident unless overwritten by an application, a number of transient commands for standard utilities were also provided. The transient commands resided in files with the extension. COM on disk, the BIOS directly controlled hardware components other than the CPU and main memory. It contained functions such as input and output and the reading and writing of disk sectors. The BDOS implemented the CP/M file system and some input/output abstractions on top of the BIOS, the CCP took user commands and either executed them directly or loaded and started an executable file of the given name. Third-party applications for CP/M were also essentially transient commands, the BDOS, CCP and standard transient commands were the same in all installations of a particular revision of CP/M, but the BIOS portion was always adapted to the particular hardware. Adding memory to a computer, for example, meant that the CP/M system had to be reinstalled with an updated BIOS capable of addressing the additional memory, a utility was provided to patch the supplied BIOS, BDOS and CCP to allow them to be run from higher memory. Once installed, the system was stored in reserved areas at the beginning of any disk which would be used to boot the system. On start-up, the bootloader would load the system from the disk in drive A. By modern standards CP/M was primitive, owing to the constraints on program size. With version 1.0 there was no provision for detecting a changed disk, if a user changed disks without manually rereading the disk directory the system would write on the new disk using the old disks directory information, ruining the data stored on the disk

24.
DOS
–
None of these systems were officially named DOS, and indeed DOS is a general term for disk operating system. MS-DOS dominated the IBM PC compatible market between 1981 and 1995, and Microsoft Windows, still ran on top of it until about 2001, dozens of other operating systems also use the acronym DOS, including DOS/360 from 1966. Others are Apple DOS, Apple ProDOS, Atari DOS, Commodore DOS, TRSDOS, see List of DOS operating systems § Other operating systems. IBM PC DOS and its predecessor, 86-DOS, resembled Digital Researchs CP/M—the dominant disk operating system for 8-bit Intel 8080, DOS instead ran on Intel 8086 16-bit processors. Starting with MS-DOS1.28 and PC DOS2.0 the operating system incorporated various features inspired by Xenix, when IBM introduced the IBM PC, built with the Intel 8088 microprocessor, they needed an operating system. Seeking an 8088-compatible build of CP/M, IBM initially approached Microsoft CEO Bill Gates, IBM was sent to Digital Research, and a meeting was set up. However, the negotiations for the use of CP/M broke down, Digital Research wished to sell CP/M on a royalty basis, while IBM sought a single license. Digital Research founder Gary Kildall refused, and IBM withdrew, Gates in turn approached Seattle Computer Products. There, programmer Tim Paterson had developed a variant of CP/M-80, the system was initially named QDOS, before being made commercially available as 86-DOS. Microsoft purchased 86-DOS, allegedly for $50,000 and this became Microsoft Disk Operating System, MS-DOS, introduced in 1981. Within a year Microsoft licensed MS-DOS to over 70 other companies, Microsoft later required the use of the MS-DOS name, with the exception of the IBM variant. IBM continued to develop their version, PC DOS, for the IBM PC, Digital Research became aware that an operating system similar to CP/M was being sold by IBM, and threatened legal action. IBM responded by offering an agreement, they would give PC consumers a choice of PC DOS or CP/M-86, side-by-side, CP/M cost almost $200 more than PC DOS, and sales were low. CP/M faded, with MS-DOS and PC DOS becoming the operating system for PCs. Microsoft originally sold MS-DOS only to original equipment manufacturers, one major reason for this was that not all early PCs were 100% IBM PC compatible. DOS was structured such that there was a separation between the specific device driver code and the DOS kernel. Microsoft provided an OEM Adaptation Kit which allowed OEMs to customize the device driver code to their particular system, by the early 1990s, most PCs adhered to IBM PC standards so Microsoft began selling MS-DOS in retail with MS-DOS5.0. In the mid-1980s Microsoft developed a version of DOS

25.
OpenVMS
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OpenVMS is a computer operating system for use in general-purpose computing. It is the successor to the VMS Operating System, that was produced by Digital Equipment Corporation, in the 1990s, it was used for the successor series of DEC Alpha systems. OpenVMS also runs on the HP Itanium-based families of computers, as of 2015, a port to the X86-64 architecture is underway. The name VMS is derived from virtual memory system, according to one of its architectural features. OpenVMS is a operating system, but source code listings are available for purchase. OpenVMS is a multi-user, multiprocessing virtual memory-based operating system designed for use in time sharing, batch processing, when process priorities are suitably adjusted, it may approach real-time operating system characteristics. The system offers high availability through clustering and the ability to distribute the system over multiple physical machines and this allows the system to be tolerant against disasters that may disable individual data-processing facilities. OpenVMS contains a user interface, a feature that was not available on the original VAX-11/VMS system. Versions of VMS running on DEC Alpha workstations in the 1990s supported OpenGL, customers using OpenVMS include banks and financial services, hospitals and healthcare, network information services, and large-scale industrial manufacturers of various products. As of mid-2014, Hewlett Packard licensed the development of OpenVMS exclusively to VMS Software Inc, VMS Software will be responsible for developing OpenVMS, supporting existing hardware and providing roadmap to clients. The company has a team of developers that originally developed the software during DECs ownership. In April 1975, Digital Equipment Corporation embarked on a project, code named Star. A companion software project, code named Starlet, was started in June 1975 to develop a new operating system, based on RSX-11M. These two projects were integrated from the beginning. Gordon Bell was the VP lead on the VAX hardware and its architecture, the Star and Starlet projects culminated in the VAX 11/780 computer and the VAX-11/VMS operating system. The Starlet name survived in VMS as a name of several of the system libraries, including STARLET. OLB. Over the years the name of the product has changed, in 1980 it was renamed, with version 2.0 release, to VAX/VMS. g. The smallest MicroVAX2000 had a 40MB RD32 hard disk and a maximum of 6MB of RAM, microVMS kits were released for VAX/VMS4.4 to 4.7 on TK50 tapes and RX50 floppy disks, but discontinued with VAX/VMS5.0

26.
VM/CMS
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VM is a family of IBM virtual machine operating systems used on IBM mainframes System/370, System/390, zSeries, System z and compatible systems, including the Hercules emulator for personal computers. The first version, released in 1972, was VM/370, or officially Virtual Machine Facility/370 and this was a System/370 reimplementation of earlier CP/CMS operating system. The current version, z/VM, is widely used as one of the main full virtualization solutions for the mainframe market. The heart of the VM architecture is a program or hypervisor called VM-CP. It runs on the hardware, and creates the virtual machine environment. VM-CP provides full virtualization of the physical machine – including all I/O and it performs the systems resource-sharing, including device management, dispatching, virtual storage management, and other traditional operating system tasks. Each VM user is provided with a virtual machine having its own address space, virtual devices, etc. A given VM mainframe typically runs hundreds or thousands of virtual machine instances, VM-CP began life as CP-370, a reimplementation of CP-67, itself a reimplementation of CP-40. Running within each virtual machine is another, guest operating system, most virtual machines run CMS, a lightweight, single-user operating system. Its interactive environment is comparable to that of a single-user PC, including a system, programming services, device access. IBMs mainstream operating systems can be loaded and run without modification, most mainframe operating systems terminate a normal application which tries to usurp the operating systems privileges. A second level instance of VM can be fully virtualized inside a virtual machine and this is how VM development and testing is done. (A second-level VM can potentially implement a different virtualization of the hardware and this technique was used to develop S/370 software before S/370 hardware was available, and it has continued to play a role in new hardware development at IBM. The literature cites practical examples of five levels deep. Levels of VM below the top are also treated as applications, a copy of the mainframe version of AIX or Linux. In the mainframe environment, these systems often run under VM. Several non-CMS systems run within VM-CP virtual machines, providing services to CMS users such as spooling, interprocess communications and they operate behind the scenes, extending the services available to CMS without adding to the VM-CP control program. By running in virtual machines, they receive the same security and reliability protections as other VM users

27.
Filesystem
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In computing, a file system or filesystem is used to control how data is stored and retrieved. Without a file system, information placed in a storage medium would be one large body of data with no way to tell where one piece of information stops, by separating the data into pieces and giving each piece a name, the information is easily isolated and identified. Taking its name from the way paper-based information systems are named, the structure and logic rules used to manage the groups of information and their names is called a file system. There are many different kinds of file systems, each one has different structure and logic, properties of speed, flexibility, security, size and more. Some file systems have been designed to be used for specific applications, for example, the ISO9660 file system is designed specifically for optical discs. File systems can be used on different types of storage devices that use different kinds of media. The most common device in use today is a hard disk drive. Other kinds of media that are used include flash memory, magnetic tapes, in some cases, such as with tmpfs, the computers main memory is used to create a temporary file system for short-term use. Some file systems are used on local storage devices, others provide file access via a network protocol. Some file systems are virtual, meaning that the files are computed on request or are merely a mapping into a different file system used as a backing store. The file system access to both the content of files and the metadata about those files. It is responsible for arranging storage space, reliability, efficiency, before the advent of computers the term file system was used to describe a method of storing and retrieving paper documents. By 1961 the term was being applied to computerized filing alongside the original meaning, by 1964 it was in general use. A file system consists of two or three layers, sometimes the layers are explicitly separated, and sometimes the functions are combined. The logical file system is responsible for interaction with the user application and it provides the application program interface for file operations — OPEN, CLOSE, READ, etc. and passes the requested operation to the layer below it for processing. The logical file system manage open file table entries and per-process file descriptors and this layer provides file access, directory operations, security and protection. The second optional layer is the file system. This interface allows support for multiple concurrent instances of physical file systems, the third layer is the physical file system

28.
Plain text
–
In computing, plain text is the data that represent only characters of readable material but not its graphical representation nor other objects. It may also include a number of characters that control simple arrangement of text. Plain text is different from formatted text, where information is included. The encoding has traditionally been either ASCII, sometimes EBCDIC, unicode-based encodings such as UTF-8 and UTF-16 are gradually replacing the older ASCII derivatives limited to 7 or 8 bit codes. Files that contain markup or other meta-data are generally considered plain-text, the use of plain text rather than bit-streams to express markup, enables files to survive much better in the wild, in part by making them largely immune to computer architecture incompatibilities. According to The Unicode Standard, Plain text is a sequence of character codes. Styled text, also known as rich text, is any text representation containing plain text completed by such as a language identifier, font size, color. For instance, Rich text such as SGML, RTF, HTML, XML, wiki markup, according to The Unicode Standard, plain text has two main properties in regard to rich text, plain text is the underlying content stream to which formatting can be applied. Plain text is public, standardized, and universally readable, Plain text represents the basic, interchangeable content of text. Plain text represents character content only, not its appearance and it can be displayed in a variety of ways and requires a rendering process to make it visible with a particular appearance. If the same plain text sequence is given to disparate rendering processes, instead, the disparate rendering processes are simply required to make the text legible according to the intended reading. This legibility criterion constrains the range of possible appearances, the relationship between appearance and content of plain text may be summarized as follows, Plain text must contain enough information to permit the text to be rendered legibly, and nothing more. The Unicode Standard encodes plain text, the distinction between plain text and other forms of data in the same data stream is the function of a higher-level protocol and is not specified by the Unicode Standard itself. The purpose of using plain text today is primarily independence from programs that require their own special encoding or formatting or file format. Plain text files can be opened, read, and edited with countless text editors, a command-line interface allows people to give commands in plain text and get a response, also in plain text. Plain text files are almost universal in programming, a code file containing instructions in a programming language is almost always a plain text file. Plain text is commonly used for configuration files, which are read for saved settings at the startup of a program. Plain text is used for much e-mail, a comment, a. txt file, or a TXT Record generally contains only plain text intended for humans to read

29.
Operating system shell
–
In computing, a shell is a user interface for access to an operating systems services. In general, operating system shells use either a command-line interface or graphical user interface, depending on a computers role and it is named a shell because it is a layer around the operating system kernel. The design of a shell is also dictated by the employed computer periphery, such as keyboard, pointing device or touchscreen. CLIs are also easier to be operated via refreshable braille display, graphical shells place a low burden on beginning computer users, and they are characterized as being simple and easy to use. With the widespread adoption of programs with GUIs, the use of shells has gained greater adoption. Since graphical shells come with certain disadvantages, most GUI-enabled operating systems provide additional CLI shells. Operating systems provide services to their users, including file management, process management, batch processing. Most operating system shells are not direct interfaces to the underlying kernel, shells are actually special applications that use the kernel API in just the same way as it is used by other application programs. A shell manages the interaction by prompting users for input, interpreting their input. Since the operating system shell is actually an application, it may easily be replaced with another similar application, on Unix-like systems, Secure Shell protocol is usually used for text-based shells, while SSH tunneling can be used for X Window System–based graphical user interfaces. On Microsoft Windows, Remote Desktop Protocol can be used to provide GUI remote access, most operating system shells fall into one of two categories – command-line and graphical. Command line shells provide an interface to the operating system. Other possibilities, although not so common, include voice user interface, the relative merits of CLI- and GUI-based shells are often debated. A command-line interface is a system shell that uses alphanumeric characters typed on a keyboard to provide instructions and data to the operating system. Operating systems such as UNIX have a variety of shell programs with different commands, syntax. Application programs may also implement a command-line interface, for example, in Unix-like systems, the telnet program has a number of commands for controlling a link to a remote computer system. Since the commands to the program are made of the same keystrokes as the data being sent to a remote computer, an escape sequence can be defined, using either a special local keystroke that is never passed on but always interpreted by the local system. The program becomes modal, switching between interpreting commands from the keyboard or passing keystrokes on as data to be processed, a feature of many command-line shells is the ability to save sequences of commands for re-use

30.
Windows 95
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Windows 95 is a consumer-oriented operating system developed by Microsoft. It was released on August 24,1995, and was a significant improvement over the companys previous DOS-based Windows products, Windows 95 merged Microsofts formerly separate MS-DOS and Windows products. It featured significant improvements over its predecessor, Windows 3.1, most notably in the user interface. It was also suggested that Windows 95 had an effect of driving other major out of business. Three years after its introduction, Windows 95 was succeeded by Windows 98, Microsoft ended support for Windows 95 on December 31,2001. The initial design and planning of Windows 95 can be traced back to around March 1992, at this time, Windows for Workgroups 3.11 and Windows NT3.1 were still in development and Microsofts plan for the future was focused on Cairo. Cairo would be Microsofts next-generation operating system based on Windows NT and featuring a new interface and an object-based file system. However, Cairo would partially ship in July 1996 in the form of Windows NT4.0, but without the object-based file system, simultaneously with Windows 3. 1s release, IBM started shipping OS/22.0. Microsoft realized they were in need of a version of Windows that could support 32-bit applications and preemptive multitasking. So the development of Windows Chicago was started and, as it was planned for a late 1993 release, became known as Windows 93. Initially, the decision was not to include a new user interface, as this was planned for Cairo, and only focus on making installation, configuration. Windows 93 would ship together with MS-DOS7.0, offering an integrated experience to the user. The first version of Chicagos feature specification was finished on September 30,1992, cougar was to become Chicagos kernel. Prior to Windows 95s official release, users in the United States had an opportunity to preview it in the Windows 95 Preview Program. For US$19.95, users would receive several 3. 5-inch floppy disks that would be used to install Windows 95 either as an upgrade from Windows 3. 1x or as a fresh installation. Participants were also given a preview of The Microsoft Network. The preview versions expired in November 1995, after which the user would have to purchase their own copy of the version of Windows 95. Windows 95 was designed to be compatible with existing MS-DOS and 16-bit Windows programs and device drivers, while offering a more stable

Computer file
–
A computer file is a computer resource for recording data discretely in a computer storage device. Just as words can be written to paper, so can information be written to a computer file, there are different types of computer files, designed for different purposes. A file may be designed to store a picture, a message, a video. Some types of files c

1.
A PNG image with an 8-bit transparency channel, overlaid onto a checkered background, typically used in graphics software to indicate transparency.

Raster graphics
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Raster images are stored in image files with varying formats. A raster is technically characterized by the width and height of the image in pixels, the printing and prepress industries know raster graphics as contones. The opposite to contones is line work, usually implemented as vector graphics in digital systems, the word raster has its origins i

1.
The smiley face in the top left corner is a raster image. When enlarged, individual pixels appear as squares. Zooming in further, they can be analyzed, with their colors constructed by adding the values for red, green and blue.

Ogg
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Ogg is a free, open container format maintained by the Xiph. Org Foundation. The creators of the Ogg format state that it is unrestricted by software patents and is designed to provide for efficient streaming and its name is derived from ogging, jargon from the computer game Netrek. The Ogg container format can multiplex a number of independent str

1.
Ogg

Multimedia
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Multimedia is content that uses a combination of different content forms such as text, audio, images, animations, video and interactive content. Multimedia contrasts with media that use only rudimentary computer displays such as text-only or traditional forms of printed or hand-produced material, Multimedia devices are electronic media devices used

Sound
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In physics, sound is a vibration that propagates as a typically audible mechanical wave of pressure and displacement, through a transmission medium such as air or water. In physiology and psychology, sound is the reception of such waves, humans can hear sound waves with frequencies between about 20 Hz and 20 kHz. Sound above 20 kHz is ultrasound an

1.
A drum produces sound via a vibrating membrane.

2.
Audio engineers in R&D design audio equipment

3.
U.S. Navy F/A-18 approaching the sound barrier. The white halo is formed by condensed water droplets thought to result from a drop in air pressure around the aircraft (see Prandtl-Glauert Singularity).

4.
Human ear

Video
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Video is an electronic medium for the recording, copying, playback, broadcasting, and display of moving visual media. Video systems vary greatly in the resolution of the display and refresh rate, video can be carried on a variety of media, including radio broadcast, tapes, DVDs, computer files etc. Video was originally exclusively a live technology

1.
Example of U-V color plane, Y value=0.5

Subtitles
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The encoded method can either be pre-rendered with the video or separate as either a graphic or text to be rendered and overlaid by the receiver. Teletext subtitle language follows the audio, except in multi-lingual countries where the broadcaster may provide subtitles in additional languages on other teletext pages. EIA-608 captions are similar, e

1.
Example of a film with subtitles (quotation dash is used for differentiating speakers)

2.
Example of speaker ID in SDH (voices are off-screen)

3.
Example of non-speech information in SDH (source is off-screen)

Text file
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A text file is a kind of computer file that is structured as a sequence of lines of electronic text. A text file exists within a file system. The end of a file is often denoted by placing one or more special characters. Such markers were required under the CP/M and MS-DOS operating systems, on modern operating systems such as Windows and Unix-like

1.
A common type of icon used to represent text files in a file explorer.

HTML
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Hypertext Markup Language is the standard markup language for creating web pages and web applications. With Cascading Style Sheets and JavaScript it forms a triad of cornerstone technologies for the World Wide Web, Web browsers receive HTML documents from a webserver or from local storage and render them into multimedia web pages. HTML describes th

1.
Tim Berners-Lee

2.
HTML (HyperText Markup Language)

Scalable vector graphics
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Scalable Vector Graphics is an XML-based vector image format for two-dimensional graphics with support for interactivity and animation. The SVG specification is a standard developed by the World Wide Web Consortium since 1999. SVG images and their behaviors are defined in XML text files and this means that they can be searched, indexed, scripted, a

1.
Scalable Vector Graphics

Source code
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In computing, source code is any collection of computer instructions, possibly with comments, written using a human-readable programming language, usually as ordinary text. The source code of a program is designed to facilitate the work of computer programmers. The source code is often transformed by an assembler or compiler into binary machine cod

1.
An illustration of Java source code with prologue comments indicated in red, inline comments indicated in green, and program statements indicated in blue

Syntax
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In linguistics, syntax is the set of rules, principles, and processes that govern the structure of sentences in a given language, specifically word order. The term syntax is used to refer to the study of such principles and processes. The goal of many syntacticians is to discover the syntactic rules common to all languages, in mathematics, syntax r

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A syntactic parse of "Alfred spoke" under the dependency formalism

Trade secret
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The precise language by which a trade secret is defined varies by jurisdiction. These three aspects are incorporated in the TRIPS Agreement in Article 39. By comparison, under U. S. law, A trade secret, §1839, has three parts, information, reasonable measures taken to protect the information, and which derives independent economic value from not be

Patent
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A patent is a set of exclusive rights granted by a sovereign state to an inventor or assignee for a limited period of time in exchange for detailed public disclosure of an invention. An invention is a solution to a technological problem and is a product or a process. Patents are a form of intellectual property, the procedure for granting patents, r

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U.S patent

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James Puckle 's 1718 early autocannon was one of the first inventions required to provide a specification for a patent.

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The plate of the Martin ejector seat of a military aircraft, stating that the design is covered by multiple patents in Britain, South Africa, Canada and "others". Dübendorf Museum of Military Aviation.

Copyright
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Copyright is a legal right created by the law of a country that grants the creator of an original work exclusive rights for its use and distribution. This is usually only for a limited time, the exclusive rights are not absolute but limited by limitations and exceptions to copyright law, including fair use. A major limitation on copyright is that c

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The Statute of Anne came into force in 1710.

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The Copyright Act of 1790 in the Columbian Centinel.

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The Pirate Publisher—An International Burlesque that has the Longest Run on Record, from Puck, 1886, satirizes the then-existing situation where a publisher could profit by simply stealing newly published works from one country, and publishing them in another, and vice versa.

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A copyright certificate for proof of the Fermat theorem, issued by the State Department of Intellectual Property of Ukraine.

Algorithms
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In mathematics and computer science, an algorithm is a self-contained sequence of actions to be performed. Algorithms can perform calculation, data processing and automated reasoning tasks, an algorithm is an effective method that can be expressed within a finite amount of space and time and in a well-defined formal language for calculating a funct

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Alan Turing's statue at Bletchley Park.

GIF
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The format supports up to 8 bits per pixel for each image, allowing a single image to reference its own palette of up to 256 different colors chosen from the 24-bit RGB color space. It also supports animations and allows a separate palette of up to 256 colors for each frame, GIF images are compressed using the Lempel–Ziv–Welch lossless data compres

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A humorous image announcing the launch of a White House Tumblr suggests pronouncing GIF with the hard "G" sound.

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A rotating globe in GIF format.

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For other uses, see GIF (disambiguation).

Royalty payment
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A royalty is a payment made by one party, the licensee or franchisee to another that owns a particular asset, the licensor or franchisor for the right to ongoing use of that asset. A royalty interest is the right to collect a stream of future royalty payments, license agreements can be regulated, particularly where a government is the resource owne

Operating system
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An operating system is system software that manages computer hardware and software resources and provides common services for computer programs. All computer programs, excluding firmware, require a system to function. Operating systems are found on many devices that contain a computer – from cellular phones, the dominant desktop operating system is

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OS/360 was used on most IBM mainframe computers beginning in 1966, including computers used by the Apollo program.

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The first server for the World Wide Web ran on NeXTSTEP, based on BSD

Microsoft Windows
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Microsoft Windows is a metafamily of graphical operating systems developed, marketed, and sold by Microsoft. It consists of families of operating systems, each of which cater to a certain sector of the computing industry with the OS typically associated with IBM PC compatible architecture. Active Windows families include Windows NT, Windows Embedde

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Screenshot of Windows 10, showing the Action Center and Start Menu

Mac OS X
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Within the market of desktop, laptop and home computers, and by web usage, it is the second most widely used desktop OS after Microsoft Windows. Launched in 2001 as Mac OS X, the series is the latest in the family of Macintosh operating systems, Mac OS X succeeded classic Mac OS, which was introduced in 1984, and the final release of which was Mac

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Steve Jobs talks about the transition to Intel processors

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OS X

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Mac OS X Lion was announced at WWDC 2011 at Moscone West.

CP/M
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Initially confined to single-tasking on 8-bit processors and no more than 64 kilobytes of memory, later versions of CP/M added multi-user variations and were migrated to 16-bit processors. The combination of CP/M and S-100 bus computers was loosely patterned on the MITS Altair and this computer platform was widely used in business through the late

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CP/M advertisement in the November 29, 1982 issue of InfoWorld magazine.

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A screenshot of CP/M-86

DOS
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None of these systems were officially named DOS, and indeed DOS is a general term for disk operating system. MS-DOS dominated the IBM PC compatible market between 1981 and 1995, and Microsoft Windows, still ran on top of it until about 2001, dozens of other operating systems also use the acronym DOS, including DOS/360 from 1966. Others are Apple DO

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FreeDOS screenshot showing the command line interface, directory structure and version information.

OpenVMS
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OpenVMS is a computer operating system for use in general-purpose computing. It is the successor to the VMS Operating System, that was produced by Digital Equipment Corporation, in the 1990s, it was used for the successor series of DEC Alpha systems. OpenVMS also runs on the HP Itanium-based families of computers, as of 2015, a port to the X86-64 a

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New logo Old logo

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VAXstation 4000 model 96 running OpenVMS 6.1 and DECwindows

VM/CMS
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VM is a family of IBM virtual machine operating systems used on IBM mainframes System/370, System/390, zSeries, System z and compatible systems, including the Hercules emulator for personal computers. The first version, released in 1972, was VM/370, or officially Virtual Machine Facility/370 and this was a System/370 reimplementation of earlier CP/

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z/VM

Filesystem
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In computing, a file system or filesystem is used to control how data is stored and retrieved. Without a file system, information placed in a storage medium would be one large body of data with no way to tell where one piece of information stops, by separating the data into pieces and giving each piece a name, the information is easily isolated and

Plain text
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In computing, plain text is the data that represent only characters of readable material but not its graphical representation nor other objects. It may also include a number of characters that control simple arrangement of text. Plain text is different from formatted text, where information is included. The encoding has traditionally been either AS

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Text file of The Human Side of Animals by Royal Dixon, displayed by the command cat in an xterm window

Operating system shell
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In computing, a shell is a user interface for access to an operating systems services. In general, operating system shells use either a command-line interface or graphical user interface, depending on a computers role and it is named a shell because it is a layer around the operating system kernel. The design of a shell is also dictated by the empl

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A graphical interface from the 1990s, which features a TUI window for a man page. Another text window for a Unix shell is partially visible.

Windows 95
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Windows 95 is a consumer-oriented operating system developed by Microsoft. It was released on August 24,1995, and was a significant improvement over the companys previous DOS-based Windows products, Windows 95 merged Microsofts formerly separate MS-DOS and Windows products. It featured significant improvements over its predecessor, Windows 3.1, mos

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The creator code is responsible for linking the file and the program that will launch when the file is double-clicked. This Mac OS window show four files of the same type code (MP3), but with four different creator codes: Audn (Audion), hook (iTunes), SCPL (SoundApp) and NSWa (Winamp).

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Home of Paul and Clara Jobs, on Crist Drive in Los Altos, California. Steve Jobs formed Apple Computer in its garage with Steve Wozniak and Ronald Wayne in 1976.

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The Apple I, Apple's first product, was sold as an assembled circuit board and lacked basic features such as a keyboard, monitor, and case. The owner of this unit added a keyboard and a wooden case.